As the title says, I am the proud owner of a new truck. This is the first vehicle I have owned that has 4wd. Yesterday I was tempted to put my truck in 4h on my way home because it was raining pretty hard and roads were a mess. I decided against that.
After I got home and did some reading it appears that had I driven my truck on pavement with 4wd engaged I may have done some damage. What I read makes sense especially since my truck has a transfer case as apposed to a center
differential(2018 STX). What I can't understand is how people drag race 4x4 trucks in 4h(youtube videos) and don't totally mess up their trucks. Not that I intend to do such things, I'm just trying to understand how it all works.
Hopefully this doesn't qualify as the dumbest question on the forum. If it does, I apologize in advance.

 

It shouldn't be a problem if you don't make any sharp turns and/or if traction is marginal. They get away with it drag racing because they are doing it in a straight line. If you put it in 4wd and turn the wheel on dry pavement, it will probably start binding and hopping.

 

There needs to be some additional information for your quarry.
A. The rear is an open carrier until you command the >>>>hard lockup<<<<< with the dash switch. There are no clutches in the rear like the older generations used.
A turn with the rear locked needs to be on a surface that offers some slippage and will cause more tire wear as well as strain on the rest of the drive line. Also stated as such in the manual.
In the (Wet/Ice) gear selection, the ABS Brake system is even used in a complex control algorithm.
B. The front lockup is a separate feature.
C. The rear in lock up {in 4H}, will only let you run up to 25 mph at which point the PCM may take the electronic throttle away from from you. It's in your owner manual. All 600 pages of lots of info you need to know.
Your truck is way advanced from the older generation such that a lot of things have been changed, added , redesigned or discontinued.
Don't take anything for granted.
.
I suspect a program change has been made to allow use of rear lockup full time for drag racing. Hint, the dash switch may be the signal to the PCM.
On an honest note, you don't want to run in 4wd on dry road and not be able to make panic steering corrections , to avoid an accident. Doing so puts everything from the steering wheel all the way to the wheels, under strain.

 

This explains a lot. Thank for taking the time to break it down barney style.
The stuff I have managed to read really just confirms your post. I just couldn't
figure out why all these people weren't breaking stuff. Again, thanks.

 

Just a quick question, since you have a new model year truck: Does it possibly have a "4WD Auto" setting (like mine has), in addition to the 4H and 4L settings? If it does, then, as I understand it, the Auto setting is pretty much like AWD and could be used most anytime, but especially on somewhat slippery pavement. I've engaged mine when driving on patchy ice/snow covered roads and haven't noticed any squirrely handling. Like the folks above have said though, I would not use 4H or 4L on hardball roads. I've engaged 4H in dry mountain dirt roads though, because I felt it improved my traction and control.

Everything I learned about driving with 4WD was on military jeeps - in pretty bad off-road conditions.

- Jack

 

Those who Drag Race use the Sport shift mode, 4H and disable the Traction Control from the dash switch in the center next to the Auto start switch.
They are running the quarter in under 14 1/2 seconds at upward of 90 + mph on street tires and 91 Octane gas on a stock motor.
Sometimes they even win over Mustangs.
It needs to be understood that this kind of power in the hands of everyday owners needs to have some respect to keep out of trouble.
The 2018 is rated at 395 Hp, 400 pound feet of torque.
The newest versions of the 5L are now 400 Hp.
You can see why the user Manual won't talk about such uses, but only from a safety point.
You can see that 400 lb/ft of max torque multiplied by each gear, then divided by 4 to each wheel reduces the slip and just keeps pulling the weight.
Even though the truck weighs a bit more than a Mustang and is less aerodynamic, dividing that much torque multiplication makes pulling the truck an equalizer of sorts.
We have a 4.6 SOHC motor modified to a bit over 400 Hp, 6 speed manual, 3.73, Hoosier slicks and about 3600 in weight feels the same as my truck for acceleration, in a 98 Mustang set up for road racing and Hill climbing. Only difference is the motor turns upwards of over 7400 rpm.